番茄社区

The U.S. Preventive Services Task Force (USPSTF) is planning to lower the age of its breast cancer screening recommendations for women at average risk.

In a draft statement released on Tuesday, the Task Force recommends mammography every other year from age 40 to 74 years -- a 'B' grade. ( recommends biennial screening starting at age 50, with individual decision-making for women in their 40s.)

The recommendations do not apply to women who have a genetic marker or syndrome associated with a high risk of breast cancer, a history of high-dose radiation therapy to the chest at a young age, or who previously had breast cancer or a high-risk breast lesion on previous biopsies.

According to the USPSTF, "new and more inclusive science about breast cancer in people younger than 50 has enabled us to expand our prior recommendation and encourage all women to get screened in their 40s. We have long known that screening for breast cancer saves lives, and the science now supports all women getting screened, every other year, starting at age 40."

"I think this is a good news story," Carol Mangione, MD, of the UCLA Fielding School of Public Health in Los Angeles, and the Task Force's immediate past chair, told 番茄社区.

"If we could get all women screened who were eligible in our country, this change in our recommendation would reduce mortality from breast cancer by about 20%," she added. "This is really quite a positive recommendation, and it should end up saving a lot of lives."

In making its recommendations, the USPSTF paid particular attention to the issue of disparities in breast cancer outcomes and the fact that Black women are 40% more likely to die of breast cancer than white women, and too often get aggressive cancers at young ages.

"That 40% difference in mortality is something that the Task Force is very concerned about, and we had for the first time with this recommendation, modeling that was constructed for Black women separate from all women, so we could look very specifically at different benefits from starting age and frequency of mammography," Mangione said.

"If anything, the benefit for starting at 40 for all women, instead of selected women, was greater for Black women than it was for all women -- but moderately beneficial for both -- so this was why we had the same recommendation for Black women as for all women," she added.

The new change would bring the influential USPSTF guidelines closer to what already happens in clinical practice, and more in line with recommendations from other leading societies, including the American College of Radiology (ACR) and Society of Breast Imaging (SBI), which recommend annual screening starting at age 40.

Current guidelines from the American Cancer Society (ACS) for women at average risk are a bit more nuanced: at age 40, all women should be given the opportunity for screening; at age 45, annual screening is recommended; then at age 55, biennial screening is recommended, but with the option to continue screening annually.

"Whatever we can do to get more women screened for breast cancer is a good thing," William Dahut, MD, chief scientific officer for the ACS, told 番茄社区, adding that the ACS is "excited" to see the USPSTF lower the screening age back to 40.

"We think lots of women are currently being screened in their early 40s, so as the guidelines become more consistent, I think that makes it easier," said Dahut.

But not everyone is pleased with the biennial decision.

In a joint statement, ACR and SBI said the new screening recommendations from the USPSTF are a "step in the right direction," but urged the Task Force to go further and recommend annual mammography screening.

Debra Monticciolo, MD, of Massachusetts General Hospital in Boston, and a member of the SBI's board of directors, told 番茄社区 she was "disappointed" with the biennial decision.

"Even if you look at their own data," said Monticciolo, "annual screening results in more deaths averted, no matter what type of screening program you put in those models."

The USPSTF also weighed in on the question of continued screening in women ages 75 and older, and supplemental screening for those with dense breasts, but concluded that current evidence is insufficient to make recommendations in either case -- 'I' grades.

The Evidence

Mangione said two streams of evidence convinced the USPSTF to change its screening recommendation.

The first was population-based data showing that while the incidence of a new breast cancer diagnosis increased gradually among women in their 40s from 2000 to 2015, it accelerated from 2015 to 2019, with an average annual increase of 2%.

"Whenever you have seen in a certain age group that the incidence of cancer is going up, you are going to think about more screening in that age group," Mangione said.

The USPSTF also used updated model-based estimates supplied by the Cancer Intervention and Surveillance Modeling Network to provide information on the benefits and harms of breast cancer screening strategies varying by ages to begin and end screening, by screening modality and interval, and by race.

According to the Task Force's draft recommendation statement, modeling data estimated that compared with biennial screening from ages 50 to 74 years, biennial screening starting at age 40 would avert an additional 1.3 breast cancer deaths per 1,000 women screened over a lifetime of screening for all women.

For Black women, modeling also estimated similar screening benefits for breast cancer mortality reduction and greater life-years gained and breast cancer deaths averted compared with all women. Specifically, biennial screening starting at age 40 years would result in 1.8 additional breast cancer deaths averted per 1,000 Black women screened.

The Task Force also said more research is needed to understand and address the higher breast cancer mortality among Black women.

Screening Frequency

Regarding screening frequency, the USPSTF noted it was unable to identify any randomized trials directly comparing annual versus biennial screening that reported morbidity, mortality, or quality-of-life outcomes. But, the use of collaborative modeling estimated that biennial screening has a more favorable balance of benefits to harms for all women and for Black women, compared with annual screening.

"If you go from every 2 years to annually, you get a little bit of increased benefit, but it comes at a pretty high rate of false positives," Mangione said.

The USPSTF's draft recommendation statement suggests that based on modeling, screening annually from ages 40 to 74 years would result in about 50% more false-positive results and 50% more overdiagnosed cases of breast cancer compared with biennial screening for all women -- with a similar increase in false-positive results and a somewhat smaller increase in overdiagnosed cases for Black women.

"At the Task Force, we look at the net benefit for the patient," Mangione said. "And the balance was better for every other year than for annual."

Monticciolo pointed out that the most intensive screening strategy (annual screening for women between the ages of 40 and 79) results in a median 41.7% reduction in breast cancer mortality for that group. On the other hand, a biennial screening strategy with digital breast tomosynthesis or digital tomography for women ages 40 to 74 years results in reductions in breast cancer mortality of 30% and 28.4%, respectively.

"That's a big difference," she said. "I don't know why you would want to have a 30% mortality reduction when you could achieve 42%."

The Task Force's draft recommendation statement, draft evidence review, and draft modeling report have been posted for public comment on the and comments can be submitted from May 9 to June 5.

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